Workaround for Cortex A76 erratum 1946160
Cortex A76 erratum 1946160 is a Cat B erratum, present in some revisions
of the A76 processor core. The workaround is to insert a DMB ST before
acquire atomic instructions without release semantics. This issue is
present in revisions r0p0 - r4p1 but this workaround only applies to
revisions r3p0 - r4p1, there is no workaround for older versions.
SDEN can be found here:
https://documentation-service.arm.com/static/5fbb77d7d77dd807b9a80cc1
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Ief33779ee76a89ce2649812ae5214b86a139e327
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index e901e0c..d859cc5 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -249,6 +249,9 @@
- ``ERRATA_A76_1868343``: This applies errata 1868343 workaround to Cortex-A76
CPU. This needs to be enabled only for revision <= r4p0 of the CPU.
+- ``ERRATA_A76_1946160``: This applies errata 1946160 workaround to Cortex-A76
+ CPU. This needs to be enabled only for revisions r3p0 - r4p1 of the CPU.
+
For Cortex-A77, the following errata build flags are defined :
- ``ERRATA_A77_1508412``: This applies errata 1508412 workaround to Cortex-A77
diff --git a/lib/cpus/aarch64/cortex_a76.S b/lib/cpus/aarch64/cortex_a76.S
index 2c99cdc..4f7f4bb 100644
--- a/lib/cpus/aarch64/cortex_a76.S
+++ b/lib/cpus/aarch64/cortex_a76.S
@@ -430,6 +430,61 @@
b cpu_rev_var_ls
endfunc check_errata_1868343
+/* --------------------------------------------------
+ * Errata Workaround for A76 Erratum 1946160.
+ * This applies to revisions r3p0 - r4p1 of A76.
+ * It also exists in r0p0 - r2p0 but there is no fix
+ * in those revisions.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_a76_1946160_wa
+ /* Compare x0 against revisions r3p0 - r4p1 */
+ mov x17, x30
+ bl check_errata_1946160
+ cbz x0, 1f
+
+ mov x0, #3
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3900002
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF00083
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ mov x0, #4
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3800082
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF00083
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ mov x0, #5
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3800200
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF003E0
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ isb
+1:
+ ret x17
+endfunc errata_a76_1946160_wa
+
+func check_errata_1946160
+ /* Applies to revisions r3p0 - r4p1. */
+ mov x1, #0x30
+ mov x2, #0x41
+ b cpu_rev_var_range
+endfunc check_errata_1946160
+
func check_errata_cve_2018_3639
#if WORKAROUND_CVE_2018_3639
mov x0, #ERRATA_APPLIES
@@ -509,6 +564,11 @@
bl errata_a76_1791580_wa
#endif
+#if ERRATA_A76_1946160
+ mov x0, x18
+ bl errata_a76_1946160_wa
+#endif
+
#if WORKAROUND_CVE_2018_3639
/* If the PE implements SSBS, we don't need the dynamic workaround */
mrs x0, id_aa64pfr1_el1
@@ -592,6 +652,7 @@
report_errata ERRATA_A76_1791580, cortex_a76, 1791580
report_errata ERRATA_A76_1165522, cortex_a76, 1165522
report_errata ERRATA_A76_1868343, cortex_a76, 1868343
+ report_errata ERRATA_A76_1946160, cortex_a76, 1946160
report_errata WORKAROUND_CVE_2018_3639, cortex_a76, cve_2018_3639
report_errata ERRATA_DSU_798953, cortex_a76, dsu_798953
report_errata ERRATA_DSU_936184, cortex_a76, dsu_936184
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 084e6e7..da0157f 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -278,6 +278,10 @@
# only to revision <= r4p0 of the Cortex A76 cpu.
ERRATA_A76_1868343 ?=0
+# Flag to apply erratum 1946160 workaround during reset. This erratum applies
+# only to revisions r3p0 - r4p1 of the Cortex A76 cpu.
+ERRATA_A76_1946160 ?=0
+
# Flag to apply erratum 1508412 workaround during reset. This erratum applies
# only to revision <= r1p0 of the Cortex A77 cpu.
ERRATA_A77_1508412 ?=0
@@ -555,6 +559,10 @@
$(eval $(call assert_boolean,ERRATA_A76_1868343))
$(eval $(call add_define,ERRATA_A76_1868343))
+# Process ERRATA_A76_1946160 flag
+$(eval $(call assert_boolean,ERRATA_A76_1946160))
+$(eval $(call add_define,ERRATA_A76_1946160))
+
# Process ERRATA_A77_1508412 flag
$(eval $(call assert_boolean,ERRATA_A77_1508412))
$(eval $(call add_define,ERRATA_A77_1508412))